Citrix has reached an agreement to acquire ISV partner RingCube, whose vDesk technology adds an additional layer of software to a virtual desktop implementation that make it far easier to allow end users to personalize the virtual desktops they use.

Although performance is the problem cited most often by analysts and IT project managers as the characteristic that either slows or kills virtual desktop rollouts, the ability for end users to personalize their desktops is at least as critical.

On traditional shared-image systems – in which everyone in a call center or bank or other place with highly standardized computing requirements – the usual approach is to run one operating-system image and set of apps on a server, then let everyone look at the same instance. They're all logged on separately and adding or reading data individually, but there's just one OS image, so users can't add their own apps, change the wallpaper, or make any other customization tweaks.

The next time they log in, any changes they could make are gone.

At the opposite end of a virtual-desktop spectrum that allows an almost infinite mix of configurations, is VDI – virtual desktop infrastructure – a system in which each user gets a separate and personal virtual desktop, just as they would in the physical computing world except that it runs on a virtual machine on a server in the data center.

VDI lets users customize their own desktops, add software, change configurations or do almost anything else they would with a physical desktop, then stores all those customizations in the storage container with the rest of the virtual machine.

Performance tends to be higher than with shared-OS models, but VDI takes up a LOT more resources – more processing power on the server, more bandwidth to shift all that data back and forth to a client machine that's not doing much work and lots and lots more storage to accommodate a separate VM for each VDI user that includes a full version of the OS, hypervisor, applications and end-user profile data.

Because it's stored in the same VHD format as a Microsoft Corp. virtual machine, vDisks are easily mobile and can be access through any Windows machine.

It can also be used to image a user's existing machine, extract the profile, data and apps data into a separate VHD that can be stored on the network and attach that to a pooled image of the operating system so every time a user logs in he or she will use the shared OS, but use a version already personalized with personal tweaks and applications.

"One of the key benefits is that it reduces the cost of storage compared to a dedicated VDI deployment, and it ultimately simplifies the move from physical desktops to virtual desktops for IT administrators," Fanelli said.

Depending on configuration, the same vDisk could support an oS running on a back-end server shared by many, a dedicated VM for one person, or the OS running on a user's own hard drive – using the vDisk VHD to back up and secure corporate data without disturbing whatever else runs on the user's machine.

Even the vDisk itself could run on a user's laptop in a BYOC situation in which the company wants a pure business environment on a piece of hardware, but the user wants personal apps to install in a portion of the machine that can't touch the virtual desktop owned by the company.

Fanelli declined to discuss packaging or integration roadmaps for the technology, but did say it would continue to work with all the products it does now from Citrix, Microsoft and RingCube competitors such as LiquidWare Labs, whose user experience management products filled a similar add-on profiling role from a third-party vendor that is now being filled by a Citrix property courtesy of RingCube.